Control pedals are typically provided in a motor vehicle, such as an automobile, which are foot operated by the driver. Separate control pedals are provided for operating brakes and an engine throttle. When the motor vehicle has a manual transmission, a third control pedal is provided for operating a transmission clutch. The control pedals are typically connected to control devices by push-pull cables, rods, or other mechanical transmission devices which convert the limited rotary motion of the pedals into useful mechanical motion at the control devices to control operation of the motor vehicle. The engine throttle is typically connected to an accelerator pedal through a mechanical cable.
There have been many attempts to introduce electrical linkages between the control pedal and the control device. Typically, an electronic position sensor converts a position of the control pedal into an electrical signal which is sent to the control device. This electrical linkage has far fewer routing limitations than the mechanical linkages. One such system is an electronic throttle control (ETC) system having an electronic pedal position sensor and electrical wires extending from the electronic pedal position sensor to a vehicle computer which controls the throttle. The electronic pedal position sensor typically provides an electrical voltage output representative of angular position of the accelerator pedal. The electronic pedal position sensor is typically a resistive potentiometer having two or more restive tracks for redundancy in providing a voltage output signal representing the position of the pedal. See U.S. Pat. No. 6,220,222, the disclosure of which is expressly incorporated herein in its entirety by reference, for an example of such an electronic pedal position sensor.
It is desirable to maintain a close tolerance of an output voltage set point for the pedal position sensor. The output voltage set point is typically at a pedal position corresponding to idle so that the set point controls engine idle speed. However, the buildup of mechanical assembly tolerances within the assembly makes it difficult to maintain the idle output voltage set point with the relatively tight tolerance. To solve this problem, a wiper of the pedal position sensor is adjusted relative to the desired pedal position during installation of the sensor until a desired output voltage is obtained for the desired pedal position. The wiper is then locked into position to maintain the positional relationship between the wiper and the pedal so that a finite output voltage at the desired pedal position (typically idle) is obtained. See U.S. Pat. No. 6,460,429, the disclosure of which is expressly incorporated herein in its entirety by reference, for an example of such an assembly method.
While this assembly method may lessen the difficulty of maintaining the desired outage voltage at the desire set point or pedal position within a close tolerance, this type of adjustment demands a mechanical interface and lock mechanism can be relatively costly to produce and assemble. Additionally, only a single output voltage set point can be set using this assembly method which means that a second important value (typically the wide open throttle position) is left to float based on the fixed relationship to the idle position. Accordingly, there is a need in the art for an improved control pedal assembly having an electronic position sensor indicating pedal position.